COMPLIANCE OF THIN-FILAMENTS IN SKINNED FIBERS OF RABBIT SKELETAL-MUSCLE
COMPLIANCE OF THIN-FILAMENTS IN SKINNED FIBERS OF RABBIT SKELETAL-MUSCLE
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DOI：
10.1016/s0006-3495(95)79975-1
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发表时间：
1995-09-01
影响因子：
3.4
通讯作者：
GOLDMAN, YE
中科院分区：
文献类型：
--
作者：
HIGUCHI, H;YANAGIDA, T;GOLDMAN, YE
细纤维的机械顺应性（刚度的倒数）是根据肌节长度在1.8到2.4 μ m之间时单个剥皮肌纤维的相对顺应性来估计的。纤维的顺应性是通过重复进行小拉伸和释放循环时肌节长度变化与张力变化的比值来计算的。当肌节长度减少到2.4 μ m以下时，纤维的顺应性降低。细纤维的顺应性可以通过这种减少来估计，因为在这个长度范围内，粗纤维和细纤维之间的重叠是完全的，所有的肌凝蛋白头都严格地结合在细纤维上。因此，肌节重叠区域的顺应性随着长度的变化是恒定的，纤维顺应性的降低是由于细丝（I带）的非重叠长度的减少。获得的细丝顺应性值表明，在2.4 μ m肌节长度时，细丝对肌节总顺应性的贡献接近55%。考虑到肌节在主动等距收缩时的柔顺性是刚性收缩时的1.25倍，细丝对肌节在等距收缩时的柔顺性的贡献约为44%。
The mechanical compliance (reciprocal of stiffness) of thin filaments was estimated from the relative compliance of single, skinned muscle fibers in rigor at sarcomere lengths between 1.8 and 2.4 mu m. The compliance of the fibers was calculated as the ratio of sarcomere length change to tension change during imposition of repetitive cycles of small stretches and releases. Fiber compliance decreased as the sarcomere length was decreased below 2.4 mu m. The compliance of the thin filaments could be estimated from this decrement because in this range of lengths overlap between the thick and thin filaments is complete and all of the myosin heads bind to the thin filament in rigor. Thus, the compliance of the overlap region of the sarcomere is constant as length is changed and the decrease in fiber compliance is due to decrease of the nonoverlap length of the thin filaments (the I band). The compliance value obtained for the thin filaments implies that at 2.4-mu m sarcomere length, the thin filaments contribute similar to 55% of the total sarcomere compliance. Considering that the sarcomeres are similar to 1.25-fold more compliant in active isometric contractions than in rigor, the thin filaments contribute similar to 44% to sarcomere compliance during isometric contraction.